Pentax 300mm f4 and 200mm f4 Lenses on a Losmandy Dovetail, focus is by a Moonlight motor and hand controller. Great portability for dark site photography. I have three adapters for this setup, one for Canon cameras, one for Nikon and a Canon to T- thread adapter to fit ZWO or similar astro cameras. There is plenty of information about Pentax lenses used for astrophotography on the internet. Some images can be seen here- https://www.narrowbandimaging.com/widefield_page.htm
Pentax 67 lenses are popular because-
1. Backfocus
These lenses have a backfocus of 84.95mm(!!!) - enough to put a filter wheel between it and the camera
2. Imaging circle
These lenses have an imaging circle of almost 8cm(!!!) - more then what most CCD cameras have. You are using the sweet spot in the middle - no distorted edge stars.
3. Quality
Being made by Pentax, the optics of these lenses is remarkable. Definitively good enough for astro-imaging.
CAMERAS ARE NOT INCLUDED
PRICE $950 plus post. PM me if you are interested.
